1. Field of the Invention
Aspects of the present invention relate to an organic light-emitting display device and a method of manufacturing the same, and more particularly, to an organic light-emitting display device including an easily and precisely deposited intermediate layer, and a method of manufacturing the same.
2. Description of the Related Art
Organic light-emitting display devices are considered to be the next-generation of display devices, since they have a wide viewing angle, a high contrast, and a quick response speed. In general, an organic light-emitting display device has a stacked structure, in which an emission layer is interposed between an anode and a cathode. A color display can thereby be realized based on a principle that light is emitted by reuniting holes injected from the anode and electrons injected from the cathode on the emission layer. However, such a structure makes it difficult to achieve efficient light emission. Thus, intermediate layers, such as an electron injection layer, an electron transport layer, a hole transport layer, and a hole injection layer, are selectively inserted between each of the electrodes and the emission layer.
However, it difficult to finely pattern a thin organic layer, such as an emission layer, or an intermediate layer, and the luminous efficiencies of red, green, and blue sub-pixels depend on the organic layers being precisely patterned. Thus, a conventional organic light-emitting display device should be improved since it is difficult to achieve a desirable driving voltage, current density, brightness, color purity, luminous efficiency, and lifetime.
An organic light-emitting display device can also be structured to include an emission layer and an intermediate layer between a first electrode and a second electrode. In this case, the first and second electrodes and the intermediate layer may be fabricated in various ways, e.g., by a deposition method. In order to manufacture an organic light-emitting display device according to the deposition method, a thin layer is formed in a predetermined pattern by closely adhering a mask, having the same pattern as the thin layer, to a plane on which the thin layer is to be formed, and then depositing a material for the thin layer on the resultant structure.
FIG. 1A is a plan view schematically illustrating an emission layer/intermediate layer pattern of a conventional organic light-emitting display device 10. FIG. 1B is a plan view schematically illustrating a mask 10Bm for depositing a blue emission layer of the conventional organic light-emitting display device 10. Referring to FIGS. 1A and 1B, pixels 11, 12, 13, and 14 of the conventional organic light-emitting display device 10 respectively include a plurality of emission layers 11R, 12R, 13R, 14R, 11G, 12G, 13G, 14G, 11B, 12B, 13B, and 14B that emit red, green, or blue light. Three sub-pixels respectively emitting red, green, and blue light from one pixel.
As described above, the emission layers 11R through 14B of the pixels 11 through 14 are formed through deposition using a mask. For example, the emission layers of red sub-pixels are simultaneously formed through deposition, the emission layers of green sub-pixels are simultaneously formed through deposition, and then the emission layers of blue sub-pixels are simultaneously formed through deposition. Thus, the conventional mask 10Bm having a plurality of openings 11Bm, 12Bm, 13Bm, and 14Bm, as illustrated in FIG. 1B, is used to obtain a blue emission layer pattern of the conventional organic light-emitting display device 10, as illustrated in FIG. 1A. Also, a mask having a plurality of openings formed at the same intervals as in the conventional mask 10Bm needs to be used in order to form each red and green emission layer pattern of the organic light-emitting display device 10.
Since the intermediate layer is also formed in the same pattern as the emission layer, a mask having a plurality of openings formed at the same intervals as in the conventional mask 10Bm needs to be used in order to obtain an intermediate layer pattern of the organic light-emitting display device 10. However, as the distances between sub-pixels become smaller, in order to manufacture high-definition display devices, the sizes of the openings of the masks become smaller. That is, referring to FIG. 1B, the widths l0 of the openings 11Bm through 14Bm become smaller. Thus, a mask having smaller openings is used in order to realize a high-definition organic light-emitting display device. However, there is a limit as to how fine-pitched a mask can be.
Also, as a mask pattern becomes finer, it is more difficult to pattern the mask and align the mask with respect to a region on which an emission layer/intermediate layer is to be deposited. Even a slight error may cause an emission layer to overlap an adjacent emission layer. Furthermore, display devices, other than an organic light-emitting display device, manufactured through such deposition also have the above-described disadvantages.